analysis of prospect of application laser induced bending ...plastic deformation of sheet metal...
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Analysis of Prospect of Application Laser induced bending forming
technology in the field of aerospace
Cailing Li 1, a *, Chao Cui 1, b, Xiaoyu Shen 1, c, Bo Wang1,Zhe Wang 1, Xiaoming
Lai1,Xin Liu1, ShuFen Liu1,Jiaowen Liu1
1Beijing spacecrafts, Beijing,China a [email protected], b [email protected], c [email protected]
Key words: Laser induced; flexible forming; spacecraft; application prospect Abstract. Laser induced forming is a kind of dieless forming technology, which is caused by the uneven internal thermal stress caused by local transient heating. In this paper, the characteristics of the laser flexible thermal forming technology are introduced, and the application prospect of the laser induced forming technology is analyzed. It lays the foundation for the popularization and application of laser induced forming technology in the field of aerospace.
Introductions
Laser induced forming technology applied to sheet metal was developed in the mid-1980s, and
it was firstly proposed by Japanese scholars. The forming mechanism is shown in Fig. 1. It is a new
flexible and dieless forming technology, based on thermal expansion and contraction and thermal
expansion characteristics of the internal organization of the material. Laser scans the metal sheet
surface by a certain track, and the thermal stress generates in the area of the heated region, which
distributions are non-uniform. Plastic deformation of sheet metal occurs under thermal stress, in
order to achieve sheet metal bending, shaping, or forming a three-dimensional complex surface.
Fig.1 a schematic view of the mechanism [1]
Sheet metal forming occupies an important proportion in the manufacture field of the
spacecrafts. In order to meet the increasingly development requirements of diverse spacecraft
structures, how to take full advantage of the performance of sheet metal forming, how to develop
new forming process, how to use computer technology to optimize the parts structure and process,
and how to detect and control the forming process, are inevitable trends of sheet metal forming
technology. Therefore, the laser induced forming technology, as a high-precision, good
International Conference on Manufacturing Science and Engineering (ICMSE 2015)
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controllability, flexible and dieless forming technology in the field of aerospace, has great
application prospect.
Characteristics of laser induced forming technology
Compared with the conventional forming process, laser induced forming technology has the
following characteristics [2-6].
1 Laser induced forming technology is a flexible and dieless forming technology. Dieless
forming greatly shortens the development cycle and reduces the costs. Flexible forming especially
suites for the development of diverse structures, single small-batch or large-lot production.
2 Laser induced forming technology is a non-contact forming technology. In the process, the
force does not act directly on the part. Springback does not occur, thus forming precision is better.
3 Laser induced forming technology is a heat accumulation process. The area of single laser
scanning and the amount of deformation are very small. The total deformation amount is formed by
a plurality of scans. And deformation is always generated in the hot state. Difficult-to-deformable
materials at room temperature can also be bent, such as titanium.
4 In theory, by optimizing process parameters and scanning traces , any bent part can be
available through laser induced forming technology, such as cylindrical, conical, spherical and other
complex three-dimensional surface parts.
5 Laser induced forming technology enables closed-loop control on the whole process of CNC
laser machine, by using infrared thermometer and shape measuring instrument. It can fix parts
online to ensure the quality and forming precision of the part.
6 Since the laser beam has a good direction and coherence, so that the laser induced forming
technology can be applied to the deformation of the structures whose space is restricted.
7 The laser induced forming technology can achieve a variety of processes at the same station,
such as bending, cutting, welding, etc.
While the research on laser induced forming technology is still at the starting stage, because of
its unique advantages, people have felt its great potential benefits. Laser forming induced
technology in the fields of aerospace, automotive, shipbuilding microelectronics and others will
have broad application prospect.
Application prospect analysis of laser induced forming technology in the field of aerospace
A large number of light alloy plate structures are applied to the spacecraft components,
especially in the manned spacecraft. Most structures are made of light alloy plate by bending. These
structures can be divided into the following four categories.
(1) Bulkheads and stringers, used to enhance the strength and stiffness of the cabin seal or seal
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structures of the spacecraft.
(2) Box-shaped products and binding belts, used for brackets of cabin equipment
(3)Large complex surface, including spherical, cylindrical, conical, and other complex shape
frame-covering and light weight panels, used for multi-surfaces of sealed cabin structures and the
stiffeners and shields of unsealed structures.
Taking into account the development requirements of the above three types of light alloy
structures of the spacecraft, in view of the characteristics of laser induced forming technology; it
has been applied to the spacecraft. This technology will have great prospect, if it can be applied to
the forming of bulkheads, stringers, box-shaped products, binding belts, frame-coverings and light
weight panels.
Laser induced forming technology for the binding belt. The binding belt is an important part,
which is applied to the unlocking device between the satellite and the rocket. Its role is to connect
the satellite and the clamps of the mating frame of the rocket to ensure a reliable connection.
Difficult-to-deformable materials at room temperature are selected, whose deformation needs to be
achieved by springback dies, shaped dies, repeated reconditioning, long development cycle and
high cost. By adjusting the process parameters, laser induced forming can quickly accomplish
precision forming of the binding belt. The shaping effect is shown in Fig.2 Laser induced forming
technology application prospect in the field of aerospace is revealed.
Fig. 2 The effect schematic of the binding belt
The laser induced forming technology for the light weight panel .The light weight panel is
the most important structure of the spacecraft sealed compartment. The light weight panel is made
from a single piece of sheet in the machining process. It has the following characteristics: flexible
geometries, various forms of the tendons, variable frame-covering thicknesses. It is easy to easy to
achieve structural weight reduction and equal strength design. It can improve sealing reliability and
Laser induced forming area
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anti-fatigue performance, and greatly enhance the strength and stiffness of the structures. Thus, light
weight panels will be the most important structures of domestic and foreign spacecraft sealed
compartments for a long period of time. Fig.3 shows the International Space Station and the new
generation of light weight panels of foreign spacecraft.
Fig.3 The International Space Station and the new generation of light weight panels of foreign spacecraft[7]
Although light weight panel structure has a series of advantages, but due to the integrated
design, the difficulty of its formation has increased dramatically. With the start of the space station
project in China, lightweight panels will present characteristics of various forms and high-precision.
At the same time, high-precision forming technology will become more urgent.
Taking into account these features of the laser induced forming technology, the column section
of the light weight panel is formed by using laser induced bending (Fig.4). The material of the light
weight panel is aluminum. The central angle is 45 °. It reveals that laser induced forming
technology has broad application prospect in the field of aerospace.
Fig.4 The light weight panel
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Conclusions
The laser induced forming technology solves the problem of the binding belt forming. It
implements a flexible high-precision forming of the light weight panel. Therefore it will have broad
application prospect in the field of aerospace, which is new and applicable to sheet metal bending.
References
[1] Nameba Y. Laser forming in space[A]. Wang C P.Proc.of Int.Conf On Lasers85ed[C]. 1986.403-407
[2] Geiger M. Synergy of laser material processing and metal forming[J]. Annals of the CIRP,1994,43 2 :563-570.
[3] Wenchuan Li and Lawrence Yao Y. Laser Forming with Constant Line Energy[J]. The International Journal of Advanced Manufacturing Technology, 2001,17 3 :196-203.
[4] Cheng P J, Lin S C. An analytical model for the temperature field in the laser forming of sheet metal[J]. Journal of Materials Processing Technology, 2000,101:260 267.
[5] Zhong Ji Shi Wu Research applied to the sheet material deformation field of laser forming [J] Plastic Engineering. 1998 5 2 33-38
[6] Hennige T, Holzer S, Vollertsen F, et al. On the working accuracy of laser bending [J]. Journal of Materials Processing Technology, 1997, 71:422-432.
[7]Damage Tolerance Behavior of Friction Stir Welds in Aluminum, NASA report.
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